Torque converters are well known in the art. Some torque converters, such as torque converters having a so-called three-pass clutch lockup design, include a clutch plate retainer that is attached to the cover of the torque converter. The retainer carries and transfers torque to clutch plates. The attachment of such retainers in prior art torque converters involved welding the retainer to the cover or attaching the retainer without any special sealing element or process. For example, see U.S. Pat. No. 5,964,329 (Kawaguchi et al.) and United States Patent Publication 2007/0251788 (Heck et al.), which Patent and Patent Publication are hereby incorporated by reference in their entireties. Attaching the retainer to the cover without any additional sealing element enables leakage between the cover and clutch plate retainer and results in poor performance of the clutch, which relies on a pressure difference between two pressure chambers on opposite sides of the piston. Welding reliably forms a fluid-tight seal, but it is expensive and may warp or deform the cover, or create spatter or other contaminants that degrade the operation of the torque converter and are difficult to remove.